Method and mechanism for sewing reverse purl



J. FOSSA.

METHOD'AND MECHANISM FOR SEWING REVERSE PURL.

APPLICATION FILED AUG 31, 19MB.

Patented Mar. 8, 1921.

2 SHEETSSHEET I.

J. FO SSA. METHOD AND MECHANISM FOR SEWING REVERSE PURL.

APPLICATION FILED M631, 1918. 1,370,528. Patented Mar. 8,1921.

2 SHEETSSHEET 2.

JOSEPH FOSS-A, OF DANVERS, MASSACHUSETTS, ASSIGNOR TO 'UNITED SHOE MACHINERY CORPORATION, OF PATERSON, NEW

01 NEW JERSEY.

JERSEY, A CORPORATION METHOD AND MECHANISM FOR SEWING REVERSE PURL.

Specification of Letters Patent.

Application filed. August 31, 1918. Serial No. 252,249.

To all whom it may concern:

Be it known that I, JosnPH F OSSA, a citizen of the United States, residin at Danvers, in the county of Essex an State of Massachusetts, have invented certain new and useful Improvements in Methods and Mechanism for Sewing Reverse Purl; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to sewing a reverse purl on buttonhole sewing machines 1n which the sewing mechanism comprises an upper needle, an under needle, and a looper for taking a loop of upper needle thread and holding it in position below the work for the passage therethrough of the under needle as it carries a loop of under thread to the upper side of the workand into position for the upper needle to pass down therethrough.

As normally operated this type of sewing mechanism sews a scam in which the purl is on the lower edge of the buttonhole slit. By the use of a comparatively light upper thread tension and a heavy under thread tension the purl may be reversed or brought to the upper edge of the buttonhole slit, as is sometimes desirable in doing special work. This heavy tension is objectionable, however, particularly during the spacing of the work. It is accordingly the object of the present invention to provide for sewing a reverse purl without the use of an abnormal under thread tension which will interfere with the ready spacing of the work. To this end the invention contemplates completing the taking up of the upper neeedle thread to tighten the loop through which the under thread has been passed and then relieving the tension on the upper thread before the looper releases the loop through which the under needle is passing. Suflicient slack thread is thus retained in the latter loop of upper needle thread to reach to the upper side of the work when the under needle returns and tightens the loop of under needle thread. Consequently, the loop of upper needle thread is readily drawn to the upper side of the work by the tightening of the loop of under needle thread without any abnormal tension on the under thread. The upper needle thread is preferably thus taken up and released by a take-up acting to take up the thread and to draw thread through the tension for the next stitch while the looper still holds the loop of thread through which the under needle is passing.

The invention will be readily understood from the following detailed description of the construction and mode of operation of the mechanism shown in the accompanying drawings.

Inthe drawings, Figure l is a side elevat1on showing so much of a buttonhole sewmg machlne as is necessary to illustrate the applicatlon of the present invention thereto; Fig, 1s a detail view of the take-up and the auxlllary slack thread controlling device; and Figs. 3 and 15 are illustrating the mode of operation of the thread handling devices in sewing a reverse purl overseam.

In the drawings the invention is shown as applied to the buttonhole sewing machine shown and described in Patent N 0. 1,063,880, June 3rd, 1913. The sewing mechanism of th1s machine comprises the upper needle 2, the under needle 1, and the looper 6, which are constructed and operate as fully explalned in said patent. The upper needle thread. leads from the upper end of the needle bar over an auxiliary slack thread controller 8 which is in the form of a bent wire arranged to be engaged by the thread durlng the downward stroke of the needle bar. The thread leads from controller through two thread guides 10 to the thread tension device 12. Between the two thread guides 10 the thread is acted upon by a combined take-up and slack thread controller 14 which is carried by the crank on the sewing shaft 16 through which the under needle mechanism is operated. The location of this combined take-up and thread controller and the .manner in which it is mounted on the crank corresponds to the location and manner of mounting the slack thread controller shown and described in the above patent. As shown, the take-up and controller comprises a wire frame provided with a horizontal portion 18 which substantially corresponds in its action upon the thread to the slack thread controller of diagrammatic views the auxiliary.

Patented Mar. 8, 1921.

the patent. The frame is also provided with a vertical thread en aging portion 20 which acts upon the thread I guides 10 to take up the thread and to draw thread through the tension for the next stitch, this part being timed to act on the thread while the looper still retains a loop of thread below the work." The lower end of the take-up part of the wire frame is so located that it passes from engagement with and releases the thread just before the looper releases the loop of thread below the work.

The mode of operation in sewing the seam is illustrated diagrammatically in Figs. 3 to 14. Assuming that the cycle begins with the parts in the position indicated in Figs. 3 and 6, in which the under needle is in its retracted position, the looper is holding a 100 of upper needle thread in position for tile passage therethrough of the under needle, the upper needle is nearly at the limit of its upward stroke, and the takeup is in the position indicated in Fig. 1; The mode of operation is as follows: The under needle moves upward into the position indicated in Fig. 4, and during this movement the upper needle completes its upward movement. The take-up moves from the position of Fig. 1 to the position of Fig.

4, and tightens the loop 22 of the preceding loop of upper needle thread, while the loopercontinues to hold the loop 24 through which the under needle is passing. Up to this time slack thread has been retained in the loop 22 so that this loop has been long enough to reach to the upperside of the work, as will presently appear. The purl formed by the interlacing of the under loop of upper needle thread with the under needle thread is therefore readily drawn to the upper side of the work by a comparatively light ull on the under needle thread, as will a so appear. While the looper is still holding the loop 24 the take-up 20 completes its taking-up action and the thread passes from the lower' end of the take-up and into the opening above the slack thread controller 18, thus relieving the tension on the upper needle thread before the loop 24 is released by the looper. This loop remains slack while the upper needle passes down through the loop of under thread, as indicated in Figs. 9 and 10, and while the looper takes the loop 26 of upper needle thread and carries it into position above the under needle which has meanwhile been. retracted to its lower position, the upgier needle also returning to the position of igs. 3 and 11. As the under needle completes its backward stroke it tightens the loop 28 of under needle thread and thereby draws a bight of the loop 24 of the upper needle thread to the upper side of the work. The loop 24 in Figs. 11 and 14 now corresponds to the loop 22 of Figs. 3 and 6, the cycle having been completed.

between the stationary This loop is tightened by the action of the take-up while t e loop'26 is retained by the looper, and while the under needle is passing the succeeding loop of under needle threadup through the loop 26, the take-up acting to relieve the tension on the thread before the looper releases the loop 26, so that thisloop in turn remains slack and of sufficient length to'be drawn to the upper side of the work by the pull on the under needle thread as this needle again reaches its retracting position.

After the take-up has acted and released the tension on the thread, as above described, the thread controller 18 acts on the thread to control theslack thread above the work so that the needle during its downward stroke will not throw out a loop of thread between its eye and the upper side of the work of s'ufficient size to interfere with the pro er operation of the sewingmechanism. 0 increase the amount of thread which draws back through the eye of the needle as the needle descends, the auxiliary slack thread controller 8 is provided, and this controller is so shaped as to properly supplement the action of the controller 18 in drawing back the proper amount of thread through the eye of the upper needle.

While .it is preferred to connect the takeup with the slack thread controller in app ying the invention to the machine of the above patent, in'view of the simplicity of the resulting construction it will be understood that the thread may be taken up and the tension on the thread released at the proper times in the-sewing cycle by any suitable construction and arrangement of take-up, and that the take-up may be operated by any suitable mechanism.

What is claimed is:

1. A method of sewing, a reverse url overseam which consists in passing a 00p of upper thread down through a loop of under thread and then through the work and retaining it below the work, passing a loop of under thread up through the loop of upper thread to a position above the work for the passage down therethrough of .of upper thread down through a loop of under thread and then through the work, holding the loop below the work-passing a succeeding loop of under thread up therethrough, taking up the upper thread to tighten the preceding loop, and then relieving the tension on the thread while maintaining the held loop of sufiicient length to low the work.

4. A mechanism for sewing a reverse purl overseam comprising an upper needle for carrying a loop of thread down through the work, an under needle for carrying a loop of another thread up through the loop .of

above the work upper thread into position for the passage of the upper -needle therethrough, Y loop of upper thread below the work sufficiently long to reach to the upper side of the Work until the loop passed therethrough by the under needle is tlghtened by the retrac-- tion of the under'needle.

5. A mechanismfor sewing an overseam, a reciprocating upper needle bar, an under needle, a looper for taking a loop of thread from a needle carried by the upper needle bar-to leads and holding it .in position for the passage therethrough of the under needle,"

' carried by ing a loop of thread down through the W0 and means for maintaining the the upper endof which-the thread d a thread controller-adjacent to "the up:

per end of the needle bar having a thread deflecting surface along which the thread is the downward movement "of the needle bar.

6. A mechanism for sewing a reverse purl overseam comprislng an .upper needle, an

under needle, a looper for taking a loop of 'upper thread an 51 holding it below the work for the passage .up therethrough of the under needle, a combinedtake-u'p and thread 1 controller, and means for actuating thesame to take up and release the upper. needle thread while the loop is retained b the looper, and to thereafter control the t read during the downward stroke of the upper needle."

7. A buttonhole sewing machine, having, in combination, an upper needle for carri r an under needle for carryin a loop of thread up through the button ole slit into position above the work for the passage of the upper needle down therethrough, a looper for takinga loop of upper needle thread and holding it below the work for the passage up therethrough of the under needle, a takeup, and means for actuating the takeup to completethe taking u and release of the upper needle thread while the looper is still holding a loop of said thread below the work.

JOSE PH FOSSA. 

